Elevating tables are commonly employed in transferring lading between relatively closely spaced different levels as exemplified, for example, in transferring loads between ground level and the deck of transport vehicles and in loading dock operations generally. In such operations it is highly important that the platform be retractable as close as possible to the lower level despite the necessary presence of underlying power means for raising and lowering the platform. One or more pairs of scissors legs commonly interconnect the platform and a supporting base. These legs and the power operating means therefore require a certain amount of critical space. Heretofore, many proposals have been made in efforts to minimise this critical spacing. Attempts have been made to place the operating cylinder alongside one of the scissor legs with one end pivotally supported near the outer end of that leg and the other end connected to the midlength area of the other leg via a short strut. However, such attempts involve severe high stress problems if the platform is lowered close to the floor because the three pivot axes of the power unit are then very close to a common plane. Typical of these proposals are disclosed by U.S. Pat. Nos. to Dalrymple et al. 2,862,689; Bamford et al. 2,928,558; Clarke 2,937,852; Dale 3,032,319; Larson 3,246,876; and Wolk et al. 3,991,857.
Each of these and other less relevant prior proposals are subject to numerous disadvantages and shortcomings. Only Larson and Wolk et al recognise the desirability of interconnecting the midlengths of the pairs of scissor legs with strong torsion transmitting members to aid in maintaining the platform level under widely varying loading conditions. However, each of these prior teachings is lacking in other respects. Thus Larson lacks power operating means permitting full collapse of the load platform as well as any means for accelerating and amplifying opening of the platform from its fully collapsed position. Wolk et al does appear to provide for full collapse but does so at the expense of an objectionably costly multipart operating mechanism utilizing complex and costly camming means insertable between the two legs of each pair in an area closely adjacent the scissor pivot axis. The remaining prior proposals identified above rely upon structures and operating principles differing widely from one another and from those characterizing this invention and are subject to serious other obvious disadvantages.